Variable pitch propeller



'Ag.`25l,41936. l LJELLWOoD-aD-.yE-IIAL 2,052,454

VARIABLE 'P1-TCH PRoPELLERz v yFiled Jan. 4, 1936 2 Sh'eefs-l-Sheet 1 l 2f 1 1 @o 'za @1' ills Aug. 2.5, 1936. l. l. ELLWOOD, 2D., Er AL 2,052,454 Y Y VARIABLE FITCH PROPELLER v Filed Jari 4, 1936 sheets-sheet 2 l Y /0 /ZS Patented Aug. 25, 1936 VARIABLEl Prron PROPELLER Isaac Leonard Ellwocd'l 2d, and Blake Burton, Williams Bay, Wis.

Application January 4, 1936, serial No. 57,618

z claims. (c1. 17o-ssi The invention relates toa variable pitch propeller and more especially to an automatic pitch controlled propeller. l

The primary object of the invention is the provision of a propeller of this character, wherein through centrifugal force the angular disposition of the blades of the propeller are automatically changed so that when the propeller is in use the `'velocity of the wind when least on the blades of the propeller the centrifugal force Will be nil and as the wind increases a centrifugal action is set up due to increased rotationV of the propeller so that the blades will become automatically adjusted so as to assure a variation in the degrees of pitch of such blades dependent on the amount Aof centrifugal force exerted thereon sof asto have the propeller obtain a near or constant revolution thereby minimizing variation and wear. Another object of the invention is the provision of a propeller of this character, wherein the bladesl thereof are supported in a novel manner so that under varying wind velocity the said blades through centrifugal force will be caused to automatically change their pitch and thus assuring near constant propeller revolution, the propeller being of novel construction and `is adaptable for driving and driven purposes.

A further object of the invention is the provision of a propeller of this character, which is comparatively simple in construction, thoroughly reliable and efficient in its operation, possessing but few parts with resultant strength and durability and also one which is comparatively inexpensive to manufacture.

With these and other objects in view, the in vention consists in the features of construction, combination and arrangement of parts as will be hereinafter more fully described, illustrated in the accompanying drawings, which disclose thepreferred embodiment of the invention, and pointed out in the claims hereunto appended.

In the accompanying drawings:

Figure 1 is a-plan view of a propellerv constructed in accordance with the invention.

Figure 2 is a sectional view through one of its blades.

Figure 3 is a view similar to Figure 2 showing the blade positioned at a different angle and aul tomatically changed by centrifugal force.

Figure 4 is a perspective view of the pitch changing shaft and hub for one ofthe blades of the propeller.

propeller constituting the present invention and hereinafter fully described. i Fitted upon this shaft A is a blade carrying ring III, it having a tapered center opening II for accommodating the tapered end I2 of the shaft A, the said ring 15 v being keyed or splined upon said shaft. Rotatably fitted with the shaft I2 next to the ring I0 is a synchronizing disk I3 having formed therein tangentiallydisposed slots I4 which are preferably equally distanced or spaced from each other and have slidably iitted therein coupling' yokes I5 for the swivel connection of the annularly grooved inner end I6 of pitch changing shafts I1 which are radially arranged with relation to the ring I0 and have fixed thereto hubs I8 which are rotatably an'd slidably fitted in hollow tubular stems I9, each at its inner end being fixed in a capped bearing 20 on 'the ring IIJ. Upon this stem I9 turns a blade 2I, there being three in number in this instance for the 30 completed propeller. The blade 2| for a larger portion of its length is centrally longitudinally slitted at 22 for occupancy of the stem in said slit while the outer wider tip end 23 of the blade which carries a weight 24 in the nature of a 35 blade support is made fast by a coupling 25 with the outer end of the shaft I1 which is passed centrally through the stem I9. The blade 2l has the slit 22 widened at 26 next to the tip 23 and at- 21 next to the inner end of said blade and 4o this widened portion 21 of the slit opens through the inner end of the said blade while bridging the said widened portion 21 of the slit at opposite sides of the blade 2| are clips 28 to loosely embrace the stem I9 between annular abutments 45 29, formed on the said stem and spaced the re-l -quired distance from each other, the stem I9 at its outer end being outturned to provide an annular abutment 30 within the widened portion 26 of the slit 22 next to the tip 23 of said blade. Thus the blade 2| with its tip is slidably and rotatably `iournaled on the stern I9 and the sliding displacement of the said blade '.on the stern is limited by the annular abutments 29 and 30, respectively.

The stem Il at its inner end is fixed in its companion capped bearing!) by a screw Il having a reduced inner end 32 loosely engaged in a spiral channel or groove I3 formed in the hub Il on the control shaft I1 and this hub slides radially to produce the turning of the same with the resultant adjustment of the blades to vary the pitch of the same. Y

In the working of the inopeller under wind velocity as the same increases or decreases against the blades 2| of the propeller through centrifugal force or centrifugal action the pitch or angular disposition of the blade will be automatically changed and this coming about uby the turning of the hubs I8 on the shafts ilv which are moved by the slotted disk il, these shafts being swiveled in the yokes i5 working in the slots ilinsaiddisk i3. 1

The disk I3 has connected to it a series of coiled tensioning springs Il, these being also con nected to the ring il and function to return the blades to a neutral position as that shown in Figures 1 and 2 ofthe drawings. whence `the yokes i5 will have traveled in the slots iii to the inner ends di.' these slots, thedisk I3 being rotated in a direction by the tension of the springs 34 for this purpose.

It should be apparent from Figures l, 2 and 3 cf the drawings that when the velocita.r ci the wind increases and strikes the blades 2i this causes a momentary increase in propulsion of the propeller. Because of this increase centrifugal force causes the weighted tips 2li of the blade to move outwasdiy, thereby pulling upon the shafts l'' which rotates the disk i3 against the resistance of springs Sii. This outfzsaidmcvement of the shafts i'i through the hubs i@ thererx on engaging the pin ends S2 ci the screws ii, thatJ is to say, these pin ends 32 Working in the .grooves or channels iii in said hubs iii automatically effect a changing oi Vthe pitchxof 'the blades di so that the propellerv through pitch variation ci its blades will have n near constant revolution during the variations in the velocity oi the wind current.

The ring it has built upon its face next the disk i3 anlannular track Si for the play oi.' the said disk thereon during the changing of the position ci1 the `disk under the automatic pitch changing action of the propeller.

The stems Il for the blades 2|, each has tted in its outer end a bushing il through which passes the shaft Il so as to center the shaft within the stcmjl particularly at the'outer end thereof while the hub Il centers said shaft Visi; the inner end of the stem. In the changing of the pitch of the blades 2l these have a limited reciprocating movement on the stems I! and auch movementaare restricted by the abutments 2l and Il as will'be apparent from Figures'l and 2 of drawings.

The weights 2l on the tips 23 of the blades are preferably of segmental form and are made secure by suitable fasteners 31- which pass through the weights and Vsaid tips while the rotes il are loosely held inthe slots I4 in the disk and the blades 2| radially disposed with respect I to the ring I0, which is a carrier body for the blades.

The clockwise and counter-clockwise movements of the disk. I3 result in the pitch changing of the blades as the shafts i1 are displaced and through the hubs le thereon the said shafts rotate or turn the blades 2i to the pitch necessary under ordinary action in the rotation'of the propalier.

It is, of course, understood that changes. variations and modifications may be made in the invention as come properly within the scope of the `appended claims without departing from the spirit of the said invention or sacrificing any of its advantages.

What is claimedis: Y Y

i. In a propeller of the character described a. rotary shaft, a. blade/carrying ring carried by said shaft,` a synchronizing disk rotatable with respect to said ring and having tangentially disposed slots, coupling yokes swiveled in said slots, pitch changing shafts radially supported with relation to said ring, tubular stems about said pitch changing shafts, propeller blades rotatable about and shlftable on said stems and having the pitch changing shafts fined thereto, hubs diced tov said pitch changing shafts and having spiral connections with the stems, spring tensioned means connected with 'the ring and disk for normally holding the coupling yokes at the inner ends of the tangential slots in said dish, l*e blades having wider portions at their outer ends and provided with longitudinal slots accommodating said stems, and weights on tile wider ends of said blades.

2. In a propeller oi the character described a rotary shaft. a blade carrying ring carried. by said shaft, a synchronizing disk rotatable with respect to said ring and having tangentiaily dieposed slots, coupling yokes swiveled in said slots, pitch changing shafts radially supported with relation to said ring, tubular stems about said pitch changing shafts, propeller blades rotatable about and shiftable on said stems and having the pitch changing shafts fixed thereto, hubs fixed to said pitch changing shafts and having spiral connections with the stems, spring tensioned means connected with the ring and disk for normally holding the coupling ydkes at the inner ends of the tangential slots in said disk, the

blades having wider portions at their outer ends and provided with longitudinal slots accommodating sald stems, weights on the wider ends of ou said blades, and bearings on the ring and accommodating the hubs of said pitch changing shafts. Y

ISAAC LEONARD EILWOOD. n. BLAKE BURTON. 

